#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <string>

using namespace std;

#define SLEEP_TIME 5000
#define LOGFILE "C:\MyServices\memstatus.txt"

SERVICE_STATUS ServiceStatus;
SERVICE_STATUS_HANDLE hStatus;

void  ServiceMain(int argc, char** argv);
void  ControlHandler(DWORD request);
int InitService();

int WriteToLog(string file_name, string input)
{
    FILE *f;
    fopen_s(&f, file_name.c_str(), "a+");
    fprintf(f, "%sn", input.c_str());
    fclose(f);
    return 0;
}

string N = "MemoryStatus";
LPWSTR Name = new wchar_t(N.size() + 1);

int main()
{
    SERVICE_TABLE_ENTRY ServiceTable[2];
    ServiceTable[0].lpServiceName = Name;
    ServiceTable[0].lpServiceProc = (LPSERVICE_MAIN_FUNCTION)ServiceMain;

    ServiceTable[1].lpServiceName = NULL;
    ServiceTable[1].lpServiceProc = NULL;
    // Start the control dispatcher thread for our service
    StartServiceCtrlDispatcher(ServiceTable);
    return 0;
}


void ServiceMain(int argc, char** argv)
{
    int error;

    ServiceStatus.dwServiceType = SERVICE_WIN32;
    ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
    ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
    ServiceStatus.dwWin32ExitCode = 0;
    ServiceStatus.dwServiceSpecificExitCode = 0;
    ServiceStatus.dwCheckPoint = 0;
    ServiceStatus.dwWaitHint = 0;

    hStatus = RegisterServiceCtrlHandler(
        Name,
        (LPHANDLER_FUNCTION)ControlHandler);
    if (hStatus == (SERVICE_STATUS_HANDLE)0)
    {
        // Registering Control Handler failed
        return;
    }
    // Initialize Service
    error = InitService();
    if (error)
    {
        // Initialization failed
        ServiceStatus.dwCurrentState = SERVICE_STOPPED;
        ServiceStatus.dwWin32ExitCode = -1;
        SetServiceStatus(hStatus, &ServiceStatus);
        return;
    }
    // We report the running status to SCM.
    ServiceStatus.dwCurrentState = SERVICE_RUNNING;
    SetServiceStatus(hStatus, &ServiceStatus);

    MEMORYSTATUS memory;
    // The worker loop of a service
    while (ServiceStatus.dwCurrentState == SERVICE_RUNNING)
    {
        char buffer[16];
        GlobalMemoryStatus(&memory);
        sprintf_s(buffer, "%d", memory.dwAvailPhys);
        int result = WriteToLog("TestFile.txt", buffer);
        if (result)
        {
            ServiceStatus.dwCurrentState = SERVICE_STOPPED;
            ServiceStatus.dwWin32ExitCode = -1;
            SetServiceStatus(hStatus, &ServiceStatus);
            return;
        }

        Sleep(SLEEP_TIME);
    }
    return;
}

// Service initialization
int InitService()
{
    int result;
    result = WriteToLog("TestFile.txt", "Monitoring started.");
    return(result);
}

// Control handler function
void ControlHandler(DWORD request)
{
    switch (request)
    {
    case SERVICE_CONTROL_STOP:
        WriteToLog("TestFile.txt", "Monitoring stopped.");

        ServiceStatus.dwWin32ExitCode = 0;
        ServiceStatus.dwCurrentState = SERVICE_STOPPED;
        SetServiceStatus(hStatus, &ServiceStatus);
        return;

    case SERVICE_CONTROL_SHUTDOWN:
        WriteToLog("TestFile.txt", "Monitoring stopped.");

        ServiceStatus.dwWin32ExitCode = 0;
        ServiceStatus.dwCurrentState = SERVICE_STOPPED;
        SetServiceStatus(hStatus, &ServiceStatus);
        return;

    default:
        break;
    }

    // Report current status
    SetServiceStatus(hStatus, &ServiceStatus);

    return;
}